The USPTO publishes patent applications. When the public comments on them, pointing out obvious prior art (something I have done), the patent office sent a form

The USPTO publishes patent applications. When the public comments on them, pointing out obvious prior art (something I have done), the patent office sent a form letter telling them that such input was not permitted. The appropriate way to challenge a patent was to wait for it to be approved, and then spend tens of millions of dollars challenging it in court, assuming you had tens of millions of dollars and many years. The new system allows random members of the public with an interest to point out prior art.